In the prior art pneumatic nail driver, the ways for beating includes a single shooting mode and a continuously shooting mode. In the single shooting mode, each time, the trigger is pressed, only one nail is beaten once. In the continuous shooting mode, the nail is beaten continuously until the nail is beaten to a designated position in the work piece.
Above said two ways can be included in the same nail driver by using a switching structure to change between the single shooting mode and the continuous shooting mode. However, these technologies are based on manual operations for changing modes. Thereby, the user is inconvenient.
Otherwise, an auto switching nail gun for changing single shooting and continuous shooting modes are used, where a press section of a safety bar extends to an output of a driver body which can press the operation surface before beating so that the safety bar will touch a movable block so that the movable rod slides. Furthermore, timing for pressing a valve rod is controlled or the movable block is buckled by another actuating hook so as to generate a single shooting mode or a continuous shooting mode. This prior art can avoid the manual switching operation and avoid the mistake beating in shooting based on the user's operation processes and habits. However, this prior art needs many components and the structure is very complicated. As the strong vibration in beating, it will shorten the lifetime of the nail driver. Further since the safety bar is formed by hooking two components without the function of adjusting the length thereof, it is imperfect and is necessary to be further improved.